Intraocular lens

ABSTRACT

An improved intraocular lens comprises a plurality of lens segments secured in a flexible and distortable frame member whereby the lens may be temporarily folded for insertion into the eye through a relatively small corneal incision. The preferred lens segments have a thickness of about 1.0 mm or less and comprise an optical material having an index of refraction of 1.5 or more.

This application is a continuation-in-part of co-pending applicationSer. No. 06/511,906, filed July 8, 1983 now abandoned.

BACKGROUND OF THE INVENTION

In my prior U.S. Pat. No. 4,159,546, there is disclosed an intraocularlens for being inserted into the posterior chamber of the eye. The useof intraocular lenses, for implantation in both the anterior orposterior chamber, has more recently become widely and successfully usedfollowing cataract surgery. In such surgery, it is most desirable tocreate a minimal corneal incision in order to reduce trauma to thecornea. Although recent developments in surgical apparatus have allowedfor removal of the cataract through an incision as small as about 2.5mm, where an intraocular lens is to be inserted, larger incisions arerequired. Although some intraocular lenses have been proposed having anoptic lens body as small as about 4 mm, lens body diameters of betweenabout 5 and about 7 mm are usually preferred. However, for insertion ofsuch a lens, the incision must be large enough to allow insertion of thelens therethrough.

In an attempt to reduce the size of the corneal incision, in myaforesaid application there is disclosed a segmented lens, allowing forsmaller individual lens segments to be inserted through a relativelysmall incision, after which the lens segments are to be assembled in theeye to form the lens body. A similar lens is shown in U.S. Pat. No.4,451,938. Although the use of such a lens appears to be beneficial, inpractice it is found to present substantial difficulties in attemptingto assemble the segments in the eye, particularly the posterior chamber.It is a purpose of the invention to provide a lens which obviates theaforesaid assembly difficulties.

SUMMARY OF THE INVENTION

The intraocular lens of the present invention comprises a lens bodyhaving a plurality of lens segments held together by flexible,distortable and preferably memory-retaining members. The lens materialis preferably of a relatively high index of refraction with the thickestpart of the lens being about 1 mm or less, substantially less than lensused heretofore. The lens may be temporarily distorted by folding orbending the flexible frame or members to overlap the segments, andinserted into the eye through a relatively small corneal incision. Onceplaced within the eye, and the distorting pressure released, the lenssegments will be readily returned to their original planar relationshipto reform the lens body. In another embodiment, a single lens segment issupported in a modified flexible and foldable frame member, FIG. 13being a sectional view taken along lines B--B of FIG. 12.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a first embodiment of the invention comprising a lensbody made up of a plurality of segments secured in a foldable framemember;

FIG. 2 is a sectional view taken along lines A--A of FIG. 1;

FIG. 3 is a sectional view of the lens of FIGS. 1 and 2 shown in atemporarily distorted condition for being inserted into the eye;

FIG. 4 is an enlarged sectional view of the edge of the lens of FIG. 1illustrating means for being secured in a frame;

FIG. 5 illustrates a segmented lens body having a different shapesecured in a frame member;

FIG. 6 illustrates another embodiment of the invention comprising asegmented lens held together by a plurality of strand members;

FIG. 7 is a side view of the lens of FIG. 6;

FIGS. 8 and 9 illustrate still another embodiment of the inventionincorporating flexible hinges for securing segmented lens;

FIGS. 10 and 11 illustrate another embodiment of the invention utilizinga thin sheet of flexible optical material secured to the lens bodyoverlying and securing the lens segments; and

FIGS. 12 and 13 illustrate a single center lens member supported in amodified flexible and foldable frame member, FIG. 13 being a sectionalview taken along lines B--B of FIG. 12.

DETAILED DESCRIPTION OF THE INVENTION

In its broad application, the improvement of the invention comprises anintraocular lens having a plurality of lens segments which are normallyheld together in a single plane to form a planar lens body and havingmeans secured to the lens segments to assist in maintaining them in sucha planar relationship when the lens is properly implanted in the eye.Such a means must be flexible and temporarily distortable to allow thelens segments to be folded in an overlapping relationship duringinsertion of the lens body through a corneal incision. The means forsecuring or holding the lens segments together is also preferably memoryretaining whereby it will return to its original shape when distortingpressure is released.

In order to achieve a folded lens assembly within suitable dimensions,the greatest thickness of the center lens segment, the thickest segmentin a convex lens, should be about 1 mm or less. The preferred lens isalso formed of three lens segments, a center segment and two sidesegments, so that the center segment is free of distortion and withoutsegment interfaces at or very near the center of the lens. To producelens of maximum 1 mm or less thickness will require use of opticalquality material of relatively high index of refraction of 1.5 orgreater and more preferably 1.6 or more. Suitable materials having sucha high refractive index include optical quality polysulfone and highquality optical glass. The width of the lens segments should also besuch that the two side segments can be folded without beingsubstantially overlapped which would unduly increase the cross-sectionalthickness of the folded lens, thereby at least partially defeating thepurpose of the invention. Thus, for example, where the overall lens bodydiameter is between about 4 and 7 mm, preferably about 6.0 mm, a centerlens segment having a width between about 2.5 and 3.5 mm with sidesegments each being between about 1.25 and about 2.0 mm are quitesuitable to avoid such overlap.

In FIGS. 1-5 there is illustrated a first embodiment in which aflexible, temporarily distortable, and memory retaining frame memberholds the assembled lens segments. In FIGS. 1 and 2, the lens 10comprises a plurality of individual lens segments 14, 16 and 18 held ina frame 12. The frame comprises any biocompatible, flexible, temporarilydistortable and memory retaining material such as polypropylene,polymethylmethacrylate, polyamide or silicone material. As alsoillustrated in FIGS. 2 and 4, the frame 12 is preferably molded orformed with an open recess 21 for receiving the outer edge of the lenssegments. It may also be desirable to incorporate additional means forsecuring the lens segments within the recessed frame, and for thispurpose, a plurality of projections 22 may be formed on the interiorrecess surface of the frame member for being received in depressionsformed on the outer surface of the lens segments. Such additionalsecuring means are useful for preventing the lens segments from beingpulled out of the frame when it is temporarily distorted. Otherretaining means may be suitable for this purpose. For example, the ringand/or the edges of the segments may be heated to create a bond betweenthe ring and segments for retention.

In FIG. 3 there is illustrated a temporarily distorted lens in which thetwo outside lens body segments 14 and 18 are folded to overlap thecenter segment 16. Fold lines 26 are formed on the frame member anddirectly overlie the interfacing edges 28 of abutting segments As shownin FIG. 1, frame member 12 is provided with four fold lines on eachoutwardly exposed frame member surface, both anterior and posterior, andthese fold lines directly overlie the two interfaces,of the threeabutting lens segments. Thus, when the lens body is folded and distortedin a configuration as shown in FIG. 3, uniform distortion of the framemember at the fold lines readily enhances the adaptability of the lensfor temporarily reducing its size for insertion in a relatively smallcorneal incision.

A similar lens is illustrated in FIG. 5, with the shape of the lens bodybeing rectangular or square. It will be also evident that the threerectangularly shaped lens segments 34, 36 and 38 are retained in agenerally rectangular frame member 32, also provided with fold lineswhich directly overlie the interfacing and abutting surfaces of therespective adjacent lens segments. The frame members of FIGS. 1 and 5incorporate flexible and memory-retaining support strands 20 forsupporting the lens when implanted in the eye, particularly in theposterior chamber. Such support members are further illustrated in myaforesaid prior patent and co-pending application, the descriptions ofwhich are incorporated herein by reference. The number of supportstrands as well as their shape may also be varied as so disclosed, asmay be the shape of the individual lens segments. The frame member inwhich the segments are secured as well as the shape of the lens bodysegments may be varied as desired. However, for the purpose of thisapplication, the abutting and interfacing surfaces of the lens segmentsare preferably parallel to one another and straight as shown in thedrawings.

FIGS. 6 and 7 illustrate an embodiment of the invention in which thelens segments are held together in their normal planar relationship withflexible and memory-retaining strands. Any number of strands may be usedand their shape is not critical, but it is preferred that each strand issecured in two adjacent lens segments. Thus, in FIG. 6, there are showndifferently shaped strands 42 and 45 which secure adjacent lens segments44 and 46. Moreover, as shown, four of the strands secure two adjacentlens segments thereby providing more substantial retention of the lenssegments in the desired planar position. Yet, such segments can bereadily folded so that the lens body is temporarily distorted as the twoouter segments 44 and 48 are folded in a manner similar to that shown inFIG. 3, and while the lens is being inserted into the eye. Moreover,with the memory-retaining feature of the strands, once the lens isinserted, like the embodiment illustrated in FIGS. 1-5, and pressure todistort the lens body relieved, the lens body will return to take itsplanar shape in the eye chamber. Suitable strand material will bepolypropylene, polymethylmethacrylate, or polyamide. In this embodiment,it is also preferred that a portion of the holding strands be of a sizesufficient to act as support members for the lens once it is implantedin the eye. For example, the longer strands 42 will be suitable forsupporting the lens in the posterior chamber.

In FIGS. 8 and 9 there is illustrated another embodiment in which thepositioning means for holding the lens segments in a normal planarposition comprises a plurality of hinges 52. Each hinge preferablyincludes a fold line 55 which directly overlies interfacing and abuttingsurfaces 56 of adjacent lens segments. Any suitable means may be usedfor securing the hinges on the lens segments. For example, projections54 formed on the hinges and inserted into depressions formed on thesurface of the lens body will be useful. The depressions may be formedso that the openings at the lens surface are slightly smaller than thediameter or largest dimension of the hinge projection whereby theprojection may be snapped into the depression or cavity for greaterstability. Alternatively, the hinge material may be heat bonded to thelens. Any number of the hinges may be used but they are preferablypositioned adjacent the outer edge of the lens body to minimize opticalinterference. The hinges are also preferably of a memory-retainingmaterial which will assist in returning the temporarily folded lenssegments to the planar position once the pressure of the distortion isreleased when the lens body is placed within the eye. A suitablematerial will be that disclosed for forming the frame member of FIG. 1.The hinges are preferably located on the flat posterior surface 50 ofthe lens body, as shown.

FIGS. 10 and 11 illustrate another embodiment utilizing a thin flexiblemembrane 62 of an optical and biocompatible material such as siliconesecured to the posterior surface of the lens body 60. Such a materialwill provide a means for holding the lens segments 61, 63 and 65together, and allows them to be folded to reduce the size of the cornealincision for insertion of the lens body into the eye. The lens segmentsmay also be easily returned to a planar position inside the eye. Themembrane or the thin sheet of optic material may be secured to thesurface of the lens segments with a biocompatible glue, or could be heatbonded to the lens.

The segmented lens illustrated in FIGS. 1 and 5 may be also produced bya process in which a laser beam is used to cut the segments while thelens is in the frame. A laser beam would cut through a unitary lens bodysecured in the frame to create the separate segments, and at the sametime be used to inscribe fold lines on the frame member.

The method of inserting the segmented lens described above is well knownto those skilled in the art and further described in my aforesaidco-pending application, the description of which is incorporated hereinby reference.

In the embodiment shown in FIGS. 12 and 13 a single lens member 72 issecured in deformable frame 70. The lens segment has a shape like thatof a center segment shown in the previous embodiments, again preferablybetween about 2.5 and 3.5 mm across or in the lateral direction andbetween about 4 and about 7 mm in the vertical direction. The frame maybe ring shaped as shown, having intergral support strands extendingtherefrom. An interior channel 74 receives the edges of the lens member.The sides of the frame are preferably thin or flattened relative to thethickness of the lens as shown. A suitable frame material is thatpreviously disclosed, while the lens may be a conventional optical lensmaterial such as polymethylmethacrylate or glass, although more highlyrefractive materials may also be used. Where conventional lens materialis used, the thickness will normally be between about 1.5 and 2.5 mm.When the lens is to be inserted, the relatively flat and flexible framesides are simply temporarily folded to overlap the lens member in amanner as previously described.

I claim:
 1. An intraocular lens comprising a segmented lens body comprising a plurality of lens segments normally held in a planar and abutting relationship, and a flexible, distortable and memory-retaining frame member separate from said lens segments and in which said lens segments are secured, said frame member having fold lines which partially overlie interfacing edges of said segments, whereby said lens segments may be temporarily overlapped for insertion through a corneal incision into the eye by folding said frame member along said fold lines.
 2. The lens of claim 1 wherein said lens body is convex shaped and comprises three segments, the center segment having a maximum thickness no greater than about 1.0 mm.
 3. The lens of claim 2 wherein the lens comprises an optical material having an index of refraction greater than about 1.5.
 4. The lens of claim 3 wherein said lens material is selected from the group consisting of polysulfone and glass.
 5. The lens of claim 1 wherein said frame member extends entirely around the periphery of said lens body.
 6. An intraocular lens comprisinga segmented lens body comprising a plurality of segments having a thickness of about 1.0 mm or less, and a distortable frame member separate from said segments and in which said segments are secured, said frame member having fold lines which partially overlie interfacing edges of said segments, said lens body and said frame member normally lying in a single plane and being temporarily distortable to a shape in which said frame member and said segments are overlapped.
 7. The lens of claim 6 wherein the lens body comprises an optical material having an index of refraction greater than about 1.5.
 8. The lens of claim 7 wherein said material is selected from the group consisting of polysulfone and glass.
 9. The lens of claim 6 wherein said frame member includes an open recess in which the edges of said segments are received.
 10. The lens of claim 9 wherein each of said segments includes one or more depressions and said frame member includes a plurality of projections received in different ones of said depressions for securing said segments in said frame member.
 11. The lens of claim 10 wherein said projections are formed along the surface of said recess.
 12. The lens of claim 6 wherein said frame member includes a plurality of outwardly extending support members.
 13. The lens of claim 12 wherein said support members are integral with said frame member.
 14. The lens of claim 9 wherein said lens segments have interfacing abutting edges extending between the segments.
 15. The lens of claim 6 including a plurality of haptic support members secured to said segments.
 16. The lens of claim 6 wherein said frame member comprises polypropylene.
 17. The lens of claim 6 wherein said frame member comprises polymethylmethacrylate.
 18. The lens of claim 6 wherein said frame member comprises polyamide.
 19. A method of producing a lens of claim 6 comprising:securing a lens body in said frame member, cutting said lens body to form said lens segments, and scribing said frame member to fomr fold lines thereon.
 20. The lens of claim 6 wherein said frame member extends entirely around the periphery of said lens body.
 21. A method of implanting an intraocular lens of claim 1 comprising folding said frame member along said fold lines whereby said lens segments are overlapped, inserting the folded lens into the eye through a corneal incision, and opening said lens whereby said lens segments and frame member lie along a common plane.
 22. A method of implanting a lens of claim 6 comprising folding said frame member along said fold lines whereby said segments are overlapped, inserting the folded lens through a corneal incision, and unfolding said frame member whereby said segments and said frame member lie in a common plane. 